Security seal unit with optical fibre

ABSTRACT

The invention relates to an optical fiber sealing unit that contains a basic bundle consisting of light-transmitting fibers, a signalling bundle also consisting of light-transmitting fibers, a cable sheath, and receiving bodies positioned at both ends of the cable sheath. The receiving bodies have an accepting space suitable for the fixing of at least some of the light-transmitting fibers, and a transmitting body that allows light to pass through it. The basic bundle and the signalling bundle are arranged in the cable sheath, and the one end and the other end of the basic bundle are each fixed in the accepting space of a receiving body in such a way that they cannot move, one end of the basic bundle being fitted to the transmitting body of one of the receiving bodies, and the other end of the basic bundle being fitted to the transmitting body of the other receiving body. One end of the signalling bundle is fixed in the vicinity of the one end of the basic bundle so as to prevent light input, while the other end of the signalling bundle is clamped into the light-transmitting output member in the vicinity of the other end of the basic bundle.

TECHNICAL FIELD

The invention relates to an optical fibre sealing unit that contains abasic bundle consisting of light-transmitting fibres, a signallingbundle also consisting of light-transmitting fibres, a cable sheath, andreceiving bodies positioned at both ends of the cable sheath. Thereceiving bodies have an accepting space suitable for the fixing of atleast some of the light-transmitting fibres and a transmitting body thatallows light to pass through it. The basic bundle and the signallingbundle are arranged in the cable sheath, and one end and another end ofthe basic bundle are each fixed in the accepting space of a receivingbody in such a way that they cannot move, one end of the basic bundlebeing fitted to the transmitting body of one of the receiving bodies andthe other end of the basic bundle being fitted to the transmitting bodyof the other receiving body.

RELATED ART

Different security sealing devices are widely used for the secure andmonitored locking of the load area of transportation devices when goodsare transported and for simply detecting unauthorised access to thetransported products. Sealing devices contain a lengthy sealing elementthreaded through loops on the wing doors or door of the loading area tobe protected of transporting vehicles, e.g. trucks, or on the tarpaulinand on the frame delimiting this, which device is then clamped in asealing structure. Numerous versions of these so-called “lead seals”have been used to this day.

There is a type of lead seal that consists of a lengthy sealing element,and a flexible signalling unit suitable for transmitting light made fromoptical fibres, in general, glass fibres. The essence is that theregularly positioned fibres at the two ends of the signalling unit aremixed up in the intermediate part of the signalling unit. By selecting asuitable light source and positioning it at one end of the undamagedsignalling unit, the light travels unobstructed and with nearly the sameintensity through the fibres, and appears at the other end of thesignalling unit. However, if the signalling unit is cut, the unorderedfibres are mixed up and the illuminating light travels through thesubsequently fitted fibres with an energy loss. Devices which operateusing this principle can be seen, among others, in the following patentdocuments: U.S. Pat. Nos. 4,161,348 and 3,854,792.

The disadvantage of the known solutions is that, although complex, therelatively precise fitting of the optical fibres after they have beencut can be solved, as a consequence of which the security sealing deviceis not able to perform what is expected of it. Due to the partiallyrestored optical light transmission, the reduction of the intensity ofthe travelling light can only be shown with difficulty, for example,with costly instruments which, however, are not available in every case.

Monitoring direct light-transmission optical seals is made moredifficult by the fact that, during the use of a cable bundle puttogether from several optical fibres, over time some of the constituentfibres get damaged or cracked, as a consequence of which the intensityof the light from the illuminating light source is reduced. As a result,when the transmitted light intensity of optical fibre security sealingunits is reduced, it is difficult to decide whether the seal has lostsome of its light-transmitting ability due to natural wear or as aconsequence of intentional damage or breakage.

Another disadvantage is that, in cases where long signalling units needto be used, e.g., fitting truck tarpaulins with security sealingdevices, then the significant distance can cause problems during theinspection of the integrity of the sealing unit.

SUMMARY OF THE INVENTION

The object of the invention is to overcome the deficiencies of the knownoptical fibre seals and to create a version that, on the one hand, makesit clearly determinable whether the sealing unit has been damaged duringa simple inspection and, on the other hand, excludes the possibility ofthe sealing unit being restored to its original or similar conditionafter it has been damaged.

The basic concept of the invention was formed by the recognition that,if the optical fibres suitable for transmitting light are divided intoseveral groups, and the groups are fixed at the ends of the closing unitin a way that is not usual, and if the optical fibres are arrangedinside the cable sheath in a new way, then the task can be solved.

In accordance with the above object, the optical fibre sealing unitaccording to the invention comprises a basic bundle consisting oflight-transmitting fibres, a signalling bundle also consisting oflight-transmitting fibres, a cable sheath, and receiving bodiespositioned at both ends of the cable sheath, the receiving bodies havingan accepting space suitable for the fixing of at least some of thelight-transmitting fibres and a transmitting body that allows light topass through it. The basic bundle and the signalling bundle are arrangedin the cable sheath, and the one end and the other end of the basicbundle are each fixed in the accepting space of a receiving body in sucha way that they cannot move. One end of the basic bundle is fitted tothe transmitting body of one of the receiving bodies and the other endof the basic bundle is fitted to the transmitting body of the otherreceiving body. The invention is set up in such a way that one end ofthe signalling bundle is fixed in the vicinity of the one end of thebasic bundle so as to prevent tight input, while the other end of thesignalling bundle is clamped into the light-transmitting output memberin the vicinity of the other end of the basic bundle.

A further feature of the sealing unit according to the invention is thatthe output member is built into the receiving body that fixes the otherend of the basic bundle, and the other end of the signalling bundle isconnected to the output member via the accepting space of the receivingbody fixing the other end of the basic bundle.

In one embodiment of the sealing unit, one end of the signalling bundleis contained in a light-proof cap.

In another embodiment of the invention, the one end of the signallingbundle is positioned in the accepting space of the receiving body thatfixes one end of the basic bundle.

From the point of view of the sealing unit, it may be desirable tocouple it with a supplementary signalling bundle made up oflight-transmitting fibres, one end of the supplementary signallingbundle being clamped into a light-transmitting output member fixed inthe vicinity of one end of the basic bundle, the other end of thesupplementary signalling bundle being positioned in the vicinity of theother end of the basic bundle in such a way as to prevent light input.

In a further embodiment of the invention, the one receiving body and theother receiving body have a closing member for fixing the locking body.

In a further embodiment of the sealing unit, the closing members areformed by closing apertures in the one receiving body and the otherreceiving body, and guide sheaths surrounding the closing apertures. Theguide sheaths are surrounded by the disordered light-transmitting fibresof the basic bundle and the signalling bundle and/or the supplementarysignalling bundle.

In a still further embodiment of the invention, the transmitting body ofthe one receiving body and the transmitting member of the otherreceiving body, as well as the output member, have optical lenses.

The sealing unit according to the invention has numerous advantageouscharacteristics. The most important of these is that due to the newlight-transmitting fibre arrangement, grouping and fixing, when thesealing unit is cut at any position, the fibres of the basic bundle andthe signalling bundle become absolutely and irrecoverably mixed up.Thus, during the cutting of the sealing unit, without using separateauxiliary devices or measurement instruments, an attempt at unauthorisedpenetration can be simply, immediately and clearly observed anddetermined.

Another advantage is that, due to the use of the signalling bundlepositioned in a new way, the original condition cannot be restored, andin this respect, there is no way of covering up the traces after a“break in” by repairing the damaged elements of the sealing unit.

Another advantage is that, in the case of a suitably set up basic bundleand signalling bundle, the sealing device according to the inventioncontains several essentially independent security and check paths, thatis, its protection and signalling ability exceed that of the traditionallead seal type security sealing devices.

BRIEF DESCRIPTION OF DRAWINGS

In the following, the invention is presented in detail in connectionwith examples on the basis of the drawings. In the drawings:

FIG. 1 shows a side view in partial section of the sealing unitaccording to the invention in side view;

FIG. 2 shows a detailed cross section of the sealing unit taken alongthe plane II—II of FIG. 1; and

FIG. 3 shows the outline of another possible embodiment of the sealingunit.

DETAILED DESCRIPTION

FIGS. 1 and 2 contain a possible embodiment of the sealing unitaccording to the invention. It can be seen that the sealing unit 1contains the basic bundle 10 and signalling bundle 20 placed in a cablesheath 30 sealed with the receiving body 40 at the one end 31 and withthe receiving body 50 at the other end 32 The basic bundle 10 is anoptical cable made up of light-transmitting fibres 13, while thesignalling bundle 20 is an optical cable made up of light-transmittingfibres 23. The receiving body 40 has an accepting space 41 for receivingthe light-transmitting fibres 13 forming the one end 11 of the basicbundle 10 as well as a transmitting body 42. In the present case, thetransmitting body 42 has an opening in the receiving body 40 that allowsthe passage of light into an area in which there is an optical lens 90fixed. The optical lens 90 of the transmitting body 42 is connected tothe one end 11 of the light-transmitting fibres 13 that form the basicbundle 10, so that light gets into the one end 11 of the basic bundle 10through the transmitting body 42.

Also, in the accepting space 41 of the receiving body 40, it ispractical for the one end 21 of the signalling bundle 20 to bepositioned and embedded among the light-transmitting fibres 13 that formthe basic bundle 10, which, however, is sealed in the light-proof cap70. Due to the effect of the light-proof cap 70, light arriving from theexternal environment cannot penetrate into the light-transmitting fibres23 of the signalling bundle 20 via the one end 21 of the signallingbundle 20.

It can also be observed in FIG. 1 that the other end 12 of the basicbundle 10 and the other end 22 of the signalling bundle 20 arepositioned in the accepting space 51 of the receiving body 50 positionedat the other end 32 of the cable sheath 30 of the sealing unit 1. Theother end 12 of the light-transmitting fibres 13 forming the basicbundle 10 is connected to the optical lens 90 fitted into thetransmitting body 52, which makes it possible for the light rays runningalong the light-transmitting fibres 13 of the basic bundle 10 to escapefrom the sealing unit 1. Beside the transmitting body 52, the receivingbody 50 also includes the output member 60, which also has an opticallens 90. The output member 60 is fixed to the other end 22 of thelight-transmitting fibres 23 of the signalling bundle 20 in such a waythat the light-transmitting fibres 23 connect to the optical lens 90.

It should be mentioned here that the optical lenses 90 do notnecessarily have to be independent components, and a solution can beimagined where the one end 11 and the other end 12 of thelight-transmitting fibres 13 of the basic bundle 10 and the other end 22of the light-transmitting fibres 23 of the signalling bundle 20 aresuitably clamped and grounded to suit the optical objective.

It can also be observed in FIG. 1 that, in the present embodiment of thesealing unit 1, the receiving body 40 and the receiving body 50 haveclosing members 3 for connecting the locking body 2. In the receivingbody 40, the closing member 3 consists of a closing aperture 43 and aguide sheath 44 surrounding the closing aperture 43, while in thereceiving body 50, it consists of a closing aperture 53 having a shapeand form the same as the closing aperture 43, and a guide sheath 54surrounding the closing aperture 53.

FIG. 2 shows that the light-transmitting fibres 13 and thelight-transmitting fibres 23 of the basic bundle 10 and the signallingbundle 20 of the sealing unit 1 in the accepting space 51 of thereceiving body 50 completely surround the guide sheath 54 thatcompletely delimits the closing aperture 53. The situation is the samewith the guide sheath 44 of the closing member 3 belonging to thereceiving body 40 of the sealing unit 1. It should be mentioned here,however, that the closing member 3 does not have to be in the form, andoperate in the same manner, as presented in FIGS. 1 and 2. Completelydifferent solutions can also be imagined. In that regard, an arrangementis possible in which the base of the external form of the receiving body40 and receiving body 50, e.g., cone, pyramid or hammer, serves as theclosing member 3, and provides for suitable closing in this way.

During the use of the sealing unit according to FIG. 1, the cable sheath30 and the receiving body 40 at the one end 31 of the cable sheath 30have to be threaded through the fixing loops of the closing body of thearea to be protected, e.g., a tarpaulin or door. Then, the closingmember 3 of the receiving body 40 and the closing member 3 of thereceiving body 50 are placed next to each other, and are locked with thelocking body 2. After the sealing unit 1 has been fixed, in the case ofa goods vehicle, the consignment can be started.

At the destination, the integrity of the sealing unit 1 can bedetermined by directing a light ray into the light-transmitting fibres13 of the basic bundle 10 via the optical lens 90 belonging to thetransmitting body 42 of one of the receiving bodies 40 of the sealingunit 1. If the basic bundle 10 is undamaged, then the light rays willtravel from one end 11 of the basic bundle 10 directly through thelight-transmitting fibres 13 to the other end 12 of the basic bundle 10,and the optical lens 90 of the transmitting body 52 of the receivingbody 50 holding the other end 12 of the basic bundle 10 will light up,while the optical lens 90 of the output member 60 of the receiving body50 will remain dark, as light cannot get into the light-transmittingfibres 23 of the signalling bundle 20 in the cable sheath 30.

If, however, during transportation, persons have tried to gain access tothe protected area by cutting the sealing unit, when the sealing unit 1is cut, the disordered and mixed up light-transmitting fibres 13 andlight-transmitting fibres 23 of the basic bundle 10 and the signallingbundle 20 will touch each other when refitted so that some of thelight-transmitting fibres 13 of the basic bundle 10 in the cross sectionof the cut meet the light-transmitting fibres 23 of the signallingbundle 20. In such a case, during the inspection at the destination, thelight getting into the transmitting body 42 of the receiving body 40 ofthe sealing unit 1 will be split up within the cable sheath 30 at theplace of damage, and will continue so that a part of it will get to thetransmitting body 52 of the other end 12 of the basic bundle 10, whilethe other part will go from the light-transmitting fibre 13 to thelight-transmitting fibre 23 and, continuing its path in the signallingbundle 20, it will arrive at the output member 60 of the receiving body50 and illuminate it. At this point, the brightness of the transmittingbody 52 will go down, and at the same time, some of the light put inwill appear at the output member 60, which will simply and reliablysignal the fact of unauthorised penetration.

In FIG. 3, a sealing unit 1 can be seen in which there is, beside thebasic bundle 10 and the signalling bundle 20, a supplementary signallingbundle 80 which has the same task as the signalling bundle 20 in thespace delimited by the cable sheath 30 having one end 31 fixed to thereceiving body 40 and the other end 32 fixed to the receiving body 50.The supplementary signalling bundle 80 is also an optical cable puttogether from light-transmitting fibres, which is practically the sameas the signalling bundle 20. One end 81 of the supplementary signallingbundle 80 is also closed with a light-proof cap 70, and its other end 82also has an output member 60. In this form—similar to that presented inFIG. 1—the one end 11 of the basic bundle 10 is connected to thetransmitting body 42 of the receiving body 40, and the other end 12 ofthe basic bundle 10 is connected to the transmitting body 52 of thereceiving body 50, while the one end 21 of the signalling bundle 20closed with a light-proof cap 70 is fitted to the receiving body 40, andthe other end 22 of the signalling bundle 20 connected to the outputmember 60 is fitted to the receiving body 50. The one end 81, closedwith a light-proof cap 70 of the supplementary signalling bundle 80, isfitted into the receiving body 40, and the output member 60 at the otherend 82 of the supplementary signalling bundle 80 is fitted into thereceiving unit 40 of the sealing unit 1.

In this embodiment, at the destination, the inspection can be carriedout from both the receiving body 40 and the receiving body 50 of thesealing unit 1. In the case of sabotage, on illuminating the basicbundle 10 from the transmitting body 42 of the receiving body 40, theprocess presented in connection with FIG. 1 is carried out. However,when light rays are directed into the light-transmitting fibres 13 ofthe basic bundle 10 from the transmitting body 52 of the receiving body50, then at the breakage point, the light travelling in thelight-transmitting fibres 13 of the basic bundle 10 from the receivingbody 50 toward the receiving body 40 goes from the light-transmittingfibres 13 to the light-transmitting fibres 83 of the supplementarysignalling bundle 80. The light going into the light-transmitting fibres83, on reaching the other end 82 fitted into the output member fixed inthe receiving body 40, lights up the optical lens 90 at the other end 82of the supplementary signalling bundle 80, and so inspection is possiblein a direction opposite to that presented in connection with FIG. 1.

The invention can be used well in all areas where the movement ofobjects needs to be prevented, in determined closed areas, e.g. the loadareas of goods vehicles and valuables, and in closed areas where thegoods and products placed in the closed areas need to be protected fromtheft and penetration.

1. An optical fibre sealing unit, comprising: a basic bundle includinglight-transmitting fibres; a signalling bundle also includinglight-transmitting fibres; a cable sheath; receiving bodies positionedat both ends of the cable sheath, each of the receiving bodies having anaccepting space suitable for fixing at least some of thelight-transmitting fibres; and a transmitting body that allows light topass through it; wherein the basic bundle and the signalling bundle arearranged in the cable sheath, and one end and another end of the basicbundle are fixed in the accepting space of a respective one of thereceiving bodies in such a way that they cannot move; wherein said oneend of the basic bundle is fitted to a transmitting body of one of thereceiving bodies, and said another end of the basic bundle is fitted toa transmitting body of another of the receiving bodies; and wherein oneend of the signalling bundle is fixed in a vicinity of said one end ofthe basic bundle so as to prevent light input, and another end of thesignalling bundle is clamped into a light-transmitting output member ina vicinity of said another end of the basic bundle.
 2. The optical fibresealing unit of claim 1, further comprising an output member built intosaid respective one of said receiving bodies that fixes said another endof the basic bundle, and said another end of the signalling bundle isconnected to the output member via said accepting space of saidrespective one of said receiving bodies that fixes said another end ofthe basic bundle.
 3. The optical fibre sealing unit of claim 2, whereinsaid one end of the signalling bundle is contained in a light-proof cap.4. The optical fibre sealing unit of claim 3, wherein said one end ofthe signalling bundle is positioned in said accepting space of saidrespective one of said receiving bodies that fixes said one end of saidbasic bundle.
 5. The optical fibre sealing unit of claim 4, furthercomprising a light-transmitting output member fixed in a vicinity ofsaid one end of the basic bundle, and a supplementary signalling bundleto which said optical fibre sealing unit is coupled, said supplementarysignalling bundle including light-transmitting fibres, one end of thesupplementary signalling bundle being clamped into thelight-transmitting output member, and another end of the supplementarysignalling bundle being positioned in a vicinity of said another end ofthe basic bundle in such a way as to prevent light input.
 6. The opticalfibre sealing unit of claim 5, wherein each of said one receiving bodyand said another receiving body has a closing member for fixing alocking body.
 7. The optical fibre sealing unit of claim 6, wherein eachclosing member is formed by a closing aperture in a respective one ofsaid one receiving body and said another receiving body, and by arespective guide sheath surrounding said closing aperture.
 8. Theoptical fibre sealing unit of claim 7, wherein each respective guidesheath is surrounded by at least one disordered light-transmitting fibreof at least one of the basic bundle, the signalling bundle and thesupplementary signalling bundle.
 9. The optical fibre sealing unit ofclaim 8, wherein each of a transmitting member of said one receivingbody and a transmitting member of said another receiving body, and theoutput member, has an optical lens.